The field of the invention is implantable plates which are attached to damaged or diseased bones, and more particularly, to bone plates attached to the surface of the pelvis.
A bone plate is a plate that is fastenable to the surface of a bone to immobilize a fracture in the bone or to support and stabilize a diseased region of the bone. The plate is typically made of a surgical grade metal such as stainless steel or titanium which has a very high tensile strength. The plate may be shaped to fit the contour of specific bone surfaces as described in U.S. Pat. Nos. 4,454,876; 4,800,874; 5,904,684 and 6,004,353, or the bone plate may be shaped by the surgeon during the operation as described in U.S. Pat. Nos. 4,573,458; 5,746,742 and 5,785,712. The bone plate is typically attached to the bone with screws that pass through judiciously placed holes in the plate.
The acetabulum is a circular-shaped ridge, or wall, of bone that defines a socket for receiving the semi-spherical head of the femur to form the hip joint. The most common fracture of the acetabulum is in its posterior wall. Multiple fractures forming small wall fragments are often found, and these multiple bone fragments must be fixed. This is currently done by cutting and bending multiple bone plates to fix the multiple bone fragments in place. This is a lengthy and challenging procedure for the surgeon. In addition, because the acetabulum wall forms part of a working joint, care must be taken when fastening each bone plate in place that none of the screws pass into the joint itself and interfere with joint operation.
The present invention is a bone plate which is shaped to fit the surface of the posterior acetabulum wall for fixing fractures therein. More particularly, the shaped bone plate includes a central portion which is shaped to fit directly over the posterior wall of the acetabulum and narrower tabs which extend in opposite directions from the central portion. Openings are provided in the central portion and the tabs for receiving mounting screws, and the openings in the central portion are shaped to guide screws away from the hip joint. Spikes are formed on the underside of the central portion to engage and fix multiple bone fragments.
A general object of the invention is to provide a bone plate which can be used to fix fractures of the posterior acetabulum wall. The wide central portion of the bone plate provides support in the fracture zone and the tabs hold it firmly in place. Multiple bone fragments are fixed to the bone plate by screws passing through openings in the central portion and spikes on its underside.
The foregoing and other objects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention, however, and reference is made therefore to the claims herein for interpreting the scope of the invention.